Fine Points of Pigments and Dye Stains

Here's an extended, in-depth discussion of the alternatives for coloring wood before applying a clear top coat. December 31, 2013

QuestionAre NGR dye concentrates the best way to stain/color wood before spraying clear conversion varnish as a topcoat? Gemini coatings carries about eight primary colors that you can mix and blend to make any color you want along with a clear base which allows it to be sprayed on. Iím wondering if this is a good way to go to create popular colors like red mahogany , espresso, etc. Iím hoping this would be a much better choice than regular wiping stains.

Forum Responses(Finishing Forum)
From contributor F:I don't know that there's any best way to stain. My first choice is a wiping stain right out of the can, usually MLC Woodsong stains. Of course with custom work that just doesn't work out most of the time. More often I end up starting out with the Woodsong color that's closest and then start adding Transtints until I get where I want to be. I'm getting better at it, but it's still a lot of trial and error. If it's a light stain I start out with the Woodsong base and just add a little until I get where I want.

Now as for trying to make traditional wood tones out of primary colors. My understanding is that's going to be very tricky. From what I've read youíre much better off buying tints in the color range you want ( burnt siennas, walnuts, etc.). Though I haven't tried it, it's just from reading finishing books, so hopefully someone else will chime in with firsthand experience.

From contributor O:Probably the best and easiest way to color wood is with a wiping stain. I prefer Mohawks but they are pretty much the same thing. They should get you to 90% of your total color. After the stain is applied you have three basic options for giving everything a similar look/color.

1. You can spray very lightly the wiping stain by reducing the air pressure and with a narrow fan. I am not a big fan of this because it has a tendency to obscure the grain.

2. The next would be to spray very lightly with an NGR dye, close to your final color. This is a better option but has a noticeable draw back in that the color that you spray on tends to appear darker once it is sealed.

3. Take the dye and after the wood is sealed add it to your topcoat and spray very lightly. This is a true representation of the color and it is quite easy to achieve a similarity on all your wood surfaces. The only drawback here is sometimes you may have to lightly scuff the surface prior to too coating.

From contributor M:The industry standard in architectural millwork and furniture finishing would be Mohawk ultra-penetrating dye stain, Sherwin Williams S61 and Keystone Nerosol. The Mohawk has alcohol in it already and is made from the Keystone product from what I understand. Keystone Nerosol and the S61 can be thinned with nearly any solvent.

Are they the best way to color wood? Impossible to say as it depends on the look you are after. A dye stain has a completely different look than a pigment stain and side by side you can tell instantly which is which. This is neither good nor bad. Pigment stains have better UV and fade resistance where dye stains have better clarity and depth. Wiping stains with dyes usually use an oil based dye which isn't very light fast as opposed to a metalized dye like the NGR stains have.

In faux painting and antiquing for example pigments are essential (although I still would use an NGR toner for final color matching in faux and as a base color in antiquing) It is also much easier to touch up a finish with a pigment stain than one with a dye. There is less chatoyance in the wood with pigment so the color doesn't shift as much when you move around it.

As far as the Gemini product I am sure it will be fine as I believe only a couple companies manufacture the dyes, Keystone and Ciba-Geigy are the ones I know of and they probably supply the dye to Gemini for their product. As far as mixing colors you should be able to match any color using the three primary colors (the manufacturers above do just that when making their wood colors to sell to end users). In reality though, a good black is needed. The three primary colors added in equal parts should make black but in reality the colors aren't perfect so you just get a dirty dark gray. Also there is no such thing as white dye (white would be the absence of all color so there wouldn't be anything in the bottle anyway) . Two part wood bleach would be as close to a white as you can get in the dye world and Ilva makes a micro ground white pigment as well.

If you have done any toning or shading with color then you have the basic technique for spraying stain already. For blotch prone woods the stain is sprayed on lightly but evenly never allowing the stain to get wet enough to pool up but just enough to evenly color. Allow to dry a few minutes and repeat until the color is achieved. For open pore wood the color is sprayed on very wet and allowed to soak into the pores to color them or you can do the same technique as above to keep the pores neutral. Just do a few samples and you will see how easy it is. Careful with the interior of boxes though, it is much easier to stain and seal flat before assembly whenever possible. You can stain the inside of a box but it takes practice to do it correctly.

From the original questioner:I would prefer using a wiping stain just because I think it would be easier to control the application as opposed to spraying it on, as is the case with Geminiís dye concentrates. I already have a bunch of Gemini dyes and clear base and donít have any of the Mohawk wiping stain, and would probably have to order each color in as the job calls for it. I guess Mohawk has their own pre-mixed colors just like minwax?
From contributor M:There are many shops that spray on pigment stains and wipe them off, there are also spray on pigment stains like ML Campbellís amazing stain that is a spray only stain. Wiping a stain creates a completely different look from spraying a stain. Make some samples and try all the different techniques and you will see what I mean. I never take anyoneís word for anything. I always do my own samples and test them to make sure.
From contributor F:ML Campbell and Mohawk and I'm sure several others do indeed have pre-mixed stains you just buy and use. You can stop by your nearest distributor, (or call), and get some literature on what colors are mixed and ready to go. I have several cans of Mohawk and I don't really notice any difference between it and MLC, but I don't do a lot of stain work either so take that for what it's worth? I buy MLC as it's the closest distributor to my shop. If there was another company closer or easier then I might be inclined to try them out as well!

Most places that provide stains should be able to mix up colors for you as well. You can bring in your sample and they can generally mix up a tint to match. Also, as I mentioned earlier you can start with something close and add tint. This is something I end up doing fairly often as I have cans of basic colors already. So if I need a dark cherry stain for instance, instead of running over and having something mixed I'll just grab a can of cherry stain and add tint to get it where I want it.

As far as the spray-only stains, you want to be careful when starting out with those. You have to have a good spray pattern and get it just right. They dry nearly instantly so there's no wiping even if you wanted to. But if youíre going for a really dark color they can be a bit more effective than wiping stains. Lastly the dyes you linked to I'm sure will work well for a variety of different applications. It's hard to offer a lot more advice as I don't know where youíre at in terms of stain and color knowledge? There are the basics of staining 101 where if you want a walnut color you use a walnut stain. Then there's the next level say staining 102 where you start mixing dyes to achieve a certain color. Then you start learn to combat certain wood tones with opposite colors. For instance, too much red/pink in mahogany can be toned down by adding green tint. I'm still at a pretty amateur stage in terms of staining. I know enough to get me by most of the time and get a nice looking product. But I still learn something every time I start a new stain job!

From contributor S:To my eye and from learning by matching and/or creating traditional type finishes, a water borne dye based system with a washcoat followed by a contrasting pigment pore filler or glaze is the most rewarding as it can provide great clarity, depth and tends to age well. Toning might then become an accent or option rather than a necessity.

The simplest system, in terms of time spent developing/formulating and executing is typically a simple wipe stain. It really depends on where you want to go. Basics: Stains do penetrate the wood, and some penetrate more than others. Water-soluble dyes penetrate the most and reside on the surface the least. One will achieve greater clarity with a water borne dye system. It is in the wood as opposed to being on it; think clothing dyes. NGR, which are typically applied by spray with a fast evaporating solvent -acetone, lt, methanol/alcohol, reside on the surface more than water though this is mitigated by their inherent transparency. Yet this system can be the trickiest as skill needs to be developed to achieve even coloring. It might be the preferable method depending on the porosity of the wood or the final look desired. At the bottom of the clarity chart would be a pigment wipe. There is penetration of course, yet it primarily sits on the surface and by nature opaque (excepting some which are sheared so finely that they appear transparent and perhaps left for another discussion).

If you are an adventurous sort let alone driven by a vision of what you want to achieve and learn, buy quality dyes - metallic/ 'light fast', yes as recommended above and play. You will in the least need the dyes for toning if you go with wipes alone for color balance. Pigments are more light-fast, and they assist in stabilizing dyes be it directly over the dye base/wood or with a washcoat in between. Do samples, tape them off and expose them to light. As to your booth - more lights than you think you need and taller -10' plus as well. Lots of room in front for maneuverability and really long items.

From the original questioner:I guess I should really be making a point of practicing different methods more instead of waiting for jobs to present themselves then running around like a headless chicken trying to find the best way to do them!
From contributor R:Water, methanol, ethanol and acetone are all polar solvents. The claim that water solubilized stains go deeper, is not quite correct. When I use NGR stains and powdered aniline dyes, I will most often use acetone. It flashes off quickly so is easier to re-apply. Methanol (wood alcohol) will likely penetrate a little deeper, but not so it makes much difference. DNA, or denatured alcohol, is ethanol with something nasty in it to keep people from drinking it. DNA is not methanol and their solubilityís are a little different for dyes. Water is the slowest to evaporate and the solubility of most aniline dyes is a little less in water.

The reason water solubilized dyes go deeper into wood is because water takes a long time to evaporate compared to acetone and alcohol and may be available to the wood a little longer. If you want it to go deeper just apply more acetone when spraying, I like dilute dyes and can adjust evenness while spraying. For this same reason I use acetone or methanol to spray since it flashes off quicker and I can see the dry effect on the work quicker and can re-coat much quicker (often while I still have the gun in my hand). The reason I do this is to build the color more efficiently with several dilute coats, and often with varying colors. This will also help avoid blotching by slowly working around difficult parts of wood and/or parts from multiple species. I find that water aggravates these tendencies since it makes wood swell and roughen more.

Another thing I noticed in this thread is the tendency (by some) to confuse dyes (transparent and soluble) with pigments (opaque and insoluble). Dyes are best used first and are generally sprayed to give more control over application. Pigments are like paint and when used need to be applied with some care to avoid concealing what you are trying to highlight or accentuate. Most wiping stains are a combination of both types. Home/DIY type stains are meant to be easy, hence the sacrifice one has to make over control. If mindless is your thing with finishing, then these are your best bet. Not all combination stains or wiping stains perform equally. There is no alternative to learning about your tools.

From the original questioner:I will explain briefly how I learned to stain/finish. Letís use mahogany for example:

Step1 - Apply minwax mahogany wiping stain. Let dry 24-48 hours.

Step2 - Add some of the stain to lacquer vinyl sanding sealer, apply as a toner until desired color is reached.

Step 3 - Seal with same vinyl sealer without any stain added to it.

Step 4 - About two coats of nitro cellulose pre-cat lacquer.

The above has worked for us for years, no complaints from clients. But then I discovered conversion varnish about a year or two ago and have basically used the same coloring system. I even substituted the lacquer sanding sealer with post-cat conversion varnish sealer. This too has worked fairly well, although I do not like using the minwax crap with my CV. This is what sparked me to try ask about the different ways to color wood, mainly NGR dye concentrates.

From contributor S:One can flood a horizontal surface with any stain, dye or pigment. Let it repose prior to wipe and one will get fairly deep penetration. I've had to pull jobs back to the base coat booth or prep area for re-sand and more than once the pigment was more difficult to remove than the water or ngr base color. Yes to methanol and acetone, and I know folks who use DA as it's often around the shop. My base point was the clarity that results with a water reduced dye. On doing side by side completed step samples, I simply prefer water over ngr. As to production issues, if one operates in a multi booth scenario - more than two or even three - especially with tow lines or whatever, then yes, ngr's are the way to go. Though that can be mitigated more than somewhat with ovens or tunnels - also most pigment stain manufactures suggest a minimum of 1/2 hour - 1 1/2 hour dry time prior to coating. With air movement a water base system is easily within that range. From the original questioner:As for how deep we want to take the art, well I want to be confident with every finish we are asked to produce, whether itís some basic color or some complicated faux finish. Iím confident that it will look great and last long. We sell ourselves as a high-end custom cabinet shop so we need to be able to produce just that.
From contributor S:Gather all the color tools that you can, create scenarios, gather samples to match and do due diligence via testing to determine their viability (light fastness, adhesion, etc.). One thing I used to do, and should still be doing, is when developing a finish on a certain species have a couple of others varieties that you can sample the same system with and check the results. Also when puzzled, or a question arises, try to work/think it through - that can be a huge learning tool.
From contributor O:If I was just starting out and trying to figure out which is best and what to use, I would be confused after reading all of the above. While it appears most have an excellent knowledge base of how things work, I find it all rather secondary. The most important thing is matching the color you want and being able to duplicate it on demand. One learns by doing and by experimenting. It's pretty easy to figure out what works best and stick with that. Remember you can use many things to achieve color. Find what you are most comfortable with and stick with it. I am surprised no one has mentioned urine. For that perfect Stickley/Greene and Greene color on QSWO there can be nothing better than urine. It's just the smell can be a little bit much at times, but it works well.

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